Fig. 1.1 shows a person standing on soft snow. The person weighs 700 N. They can wear either snowshoes or boots. (a) Calculate the pressure exerted on the s...
Question 1 Report
Fig. 1.1 shows a person standing on soft snow. The person weighs 700 N. They can wear either snowshoes or boots.
(a) Calculate the pressure exerted on the snow when the person wears snowshoes. [2]
(b) Calculate the pressure exerted on the snow when the person wears boots. [2]
(c) Explain why snowshoes prevent the person from sinking into the snow. [2]
Answer Details
(a) Pressure with snowshoes [2]
Using the pressure formula:
\(p = \dfrac{F}{A} = \dfrac{700}{0.25}\) [1]
\(p = \mathbf{2800 \text{ Pa}}\) [1]
(b) Pressure with boots [2]
\(p = \dfrac{F}{A} = \dfrac{700}{0.04}\) [1]
\(p = \mathbf{17\,500 \text{ Pa}}\) [1]
(c) Why snowshoes prevent sinking [2]
The snowshoes spread the person's weight over a much larger area (0.25 m2 vs 0.04 m2). [1] Since pressure = force / area, a larger area means a lower pressure on the snow surface. At 2800 Pa the snow can support the person without collapsing, whereas at 17 500 Pa with boots the pressure exceeds what the soft snow can bear and the person sinks. [1]
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